In one aspect the invention provides a bioreactor system for the production of tissue prostheses. The system includes a bioreactor, a culture medium reservoir coupled to the bioreactor by a first conduit and a second conduit, a pump operable to pump fluid into and draw fluid out of a pumping chamber defined in the bioreactor to generate a pulsatile flow of culture medium through the reservoir and bioreactor via said first and second conduits, one or more flow meters operable to generate flow rate signals representative of the rate of culture medium flow through one or both of said first and second conduits, and a controller arranged to receive said flow rate signals from said one or more flow meters and to control the pump means in response to said received flow rate signals to provide a desired rate of culture medium flow.